Dual band antenna for GSM and UMTS

[tiger82]

I need an antenna to be low profile (suitable to be mounted on a Helicopter) and that covers GSM upload band (880-915)and UMTS upload band (1850-1980)
A design with a circular polarization is the optimal that i can expect.

I will appreciate any idea or document,
Thank you

 

[VEBill]

Ideally you'd have hemispheric coverage with a roughly cosecant-squared elevation gain pattern. Allowing for aircraft pitch and roll, you need to allow some usable gain in the positive elevation regions too. On the other hand, given your advantageous location (~2000' AGL) a damp string might get the job done. ;-)

Are there any 'cell phone' antennas for aircraft on the market yet? They'll probably be a blade, but I'll bet that 95% of present aircraft antennas are blade.

 

[Higgler]

Sounds like something you could purchase. There's alot of dual band antennas around.
Which circular polarization? RHCP, or does it matter?

You may want to describe the installation a bit more, i.e. cut one hole, size LxWxDepth. Unit protrudes X inches above flush. Connector type ?N-f. Maybe describe how you want to mount it.

kch

 

[tiger82]

The design dimensions should be :
LxWxH : 10x10x5 cm (maximum dimensions)

For the feed type there will be a coax line that can feed the design.

So the design needed is a low profile antenna (by expample: microstrip , aperture coupled ...)and should be placed on the Helicpter on the lower part.

Any idea for he design or a paper related is a great help for me.

Thank you

 

[Comcokid]

I recently tested some dualband cellular antennas for a M2M application. There are low profile antennas from companies like Radiall/Larsen (NMO series), Mobile Mark (RMM series), and Larsen (W760 series) that may indicate 900/1700 MHz, but actually match with a <2:1 VSWR over a much, much wider frequency range. We were testing with a 12" sq ground plane. Can't state anything about the radiation pattern.

These are typically advertised for trunk mounting or vehicle mounting. I don't know how suitable they would be for an aircraft. The offering from one of these companies (I won't state which) was actually wideband - basically 800 MHz to 2 GHz when swept (!), but exhibited plastic problems when we tested at cold temperatures - we fed the data back to them and they were going to use a new plastic.

Maybe an offering from one of these companies will work. However, many times a company advertising an antenna doesn't actually make the product but private-label it from an obscure source.

 

[VEBill]

Low profile antennas for aircraft - the normal discussion.

Boss: "It MUST be low profile."

...6 months later...

Eng: "All the antennas that are available off-the-shelf are blades. A low profile version will take 22 months and cost $190k for NRE."

Boss: "The blade will be fine."

;-)